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. M y 26. 1931,. A. a. BUTTERWORTH Y 1, 06

METHOD OF CLEANING, SCALING, AND GAS FREEZING BULK CARGO TANKS 0F TANKVESSELS Filed Oct. 11. 1927 mamam. 3

Patented May 26, 1931 3 mean \STATESMPATENT OFFICE 'ARTHUR'B.BUTTERWORTH, OF HOB-T ARTHUR, TEXAS, ASSIGNOR, BY ASSIGN- MENTS, TOBUTTERWORTH SYSTEM, ING, OF WILmGTON, DELAWARE, A. CORPORA- TION OhDELAWARE 1 METHOD or CLEANING. SCALINQAND ens FREEING BULK CARGO TANKS01 mm a 1 vEssELs I Application filed October 11, 1927. Serial No.225,592.

' My invention relates to a method of clean-. ing the interior of tanksof tank vessels employed in transporting crude oil and its derivatives.i

I The tanks of vessels employed in transporting petroleum and itsdistillates may be em.- ployed in the carrying of the heavy crude or anyof the distillates obtained'therefrom, andit sometimes becomes necessaryafter a tanker has been employed in the transportation of heavy crude tocarry in this same vessel a cargo of the lighter. distillates, such asgasoline or benzine. In changing from transortation of the heavyv oil tothat of the ighter distillates, it becomes necessary to thoroughly cleanthe interior of the cargo tanks so that the distillate will not bediscolored during transportation, 'due to the residue left in the tankfrom the crude oil. 4 an The present system of cleaning the tanks of avessel of this character involves a long and laborious process which isalso expensive in its operation and which may also result in adeterioration of the hull of the vessel. 26 the old method, the firstoperation is usually to steam out the tanks by forcing into the tanks asupply of steam which is intended to make the residue oil within thetank more fluid and to "remove from the rust and scale so on theinterior of the tank, gas-forming residue which accumulates along. thesides and among the numerous plates and'the framework of the vessel. Inthis method, the steaming'is carried out for a desired period I and thenthe tanks are opened up to cool and arethen washed down' with a hosefirst from the deck and then from the bottom of the tank. After this allthe shelves, frame work, plating and sides of the tank are scraped downby hand to get the bulk of the sediment and rust from thetank; Thebottom sediment is then hauled out on deck. In

some cases caustic soda is then sprinkled on the frames, shelves,gussets, etc., or this may be done previous to the first steaming, thesteam dissolving the soda and tending to can}? the deposit with it tothe bottom of the tan 1 The tanks are-then ready to receive the liquidfor soaking and the cleaning liquid is then forced into the tank.Usually kerosene is preferred, although a distillate or other similarmixture may be employed. It is the usual practice to fill one or moretanks well up in the expansion trunk and then allow it to soak for fromsix to twenty-four hours. After this the liquid is pumped out of thetank and the steam turned on through the steam smothering line forseveral hours after which the sides are washed down with water and theparts again scraped and scaled and the sediment removed from the bottom.'This operation is repeated with a new batch of cleaning liquid and thenall the packing is renewed about the hatch covers, expansion 'joints,ullage plates, valves, etc.. This repacking of the parts becomesnecessary from the straining of the parts due to the unequal heatinginvolved in the cleaning operation, audit is found that by this methodof cleaning'the li uid accumulates in the bottom of the ta so that thelower part of the tank is kept comparatively cool, while a the upperpart is heated, and furthermore, the gathering of liquid in the bottomportion of the tank prevents this area from being cleaned when the hoseis used against the tops and sides. 5 It'is an object of myinvention toprovide a process of cleaning the interiorof tanks of this character inwhich the interior of the tank is thoroughly cleaned at all points andin which unequal heating of the tank is entirely avoided. v

It is also an object to dispensewith the necessity of scraping and thehand work in volved in the old method of cleaning.

It is another object to simplify the labor and cheapen the cost ofcleaning the interior of tanks of the character stated.

It is desired to clean the interior of the tank by, force of streams ofliquid directed against the sides under high pressure and in which theliquid thus usedin cleaning is simultaneously removed from the tanktogether with the sediment obtained in the cleaning operation. w 7Referring to the drawings herewith, I have shown somewhatdiagrammatically a cross section of the hull of a tanker showing theap-.

paratus by means of which my process maybe carried into execution.

In the drawing the hull of a ship is designated by the numeral 1, thecross section showingthe two tanks, one on each side of the interior ofthe vessel, separated by a central partition 4. The bottom of the vesselis ordinarily somewhat flattened, as shown at 2, the deck beingindicated at 3.

It is a'common feature in the usual tanker to provide wing tanks on theupper outer portions of the main tanks, and such a tank is shown in thedrawings on each of the main I tank sections 27. These tanks have abottom 8 and an inner side wall 7 the outer wall corresponding with thatof the main tank. In carrying out my invention, the wing tanks are usedto contain the cleaning liquid, although it is to be understood thatthis liquid may be contained in a separate container or tank on the deckor in an adjacent vessel. The liquid employed in the cleaning is placedin this tank and may be heated through a heating coil 26 connected bymeans of the pipe to a source of supply of steam or other heating fluid.The cleaning fluid is circulated from the wing tank by means of a pump 9having a suction line 10 directed into the wing tank, and an outlet line11 through which the liquid from the pump may be directed into the pipe12 and downwardly to the nozzles 15 through which the liquid isdischarged in a solid stream against the sides of the tank. It will benoted that the two nozzles 15, one at each side of the main carryingline 13, are directed in opposite directions. This type of cleaningdevice is shown in my previous Patent No. 1,557,240, issued October13th, 1925, and the exact construction thereof is not apart of thepresent invention. The connecting T 1 1 is secured rigidly upon the pipe13, the pipe 13 being rotated through a shaft 18 at the upper endthereof and the pipe 12, through which the fluid flows from the pipe 11,is held sta tionary. The lower end of the pipe 12 is formed with astationary gear 17 thereon which is engaged by a gear16 upon one of thenozzles. The rotation of the shaft 18 and the tube 13 leading therefromrotates the T 14 and the nozzles and the engagement between the gear 16and the stationary gear 17, while the tube 13 is rotated, will cause thenozzles to be rotated in planes parallel with the pipe 12. It is to beunderstood that the gears 16 and 17 are not of exactly the same size sothat the courses of the streams issuing from the nozzles 15 will take adifferent path on each revolution which they make about the centralshaft 13.

The shaft 18 is rotated by means of a gear 19 thereon connected with agear 20 engaged therewith and said gear 20 may be rotated by any desiredmeans, such as the crank 21, or

through connection with some source of power such as an air engine orsimilar apparatus.

Itwill be noted that the cleaning appara- I tus is supported upon theupper end of the hatch way 5 but it is to be understood that it may bemounted in any desired manner, the object being to locate the nozzles 15in such position within the tank that the streams of cleaning fluid maybe directed under high pressure against the whole interior of the tank,it being found that in apparatus of this kind the whole inner side ofthe tank will be engaged by the streams of liquid during the rotation ofthe nozzles so that all sediment scale and dirt will be removed.

Simultaneously with the cleaning of the interior of the tank, I removethe cleaning liquid at once'from the bottom of said tank. This is doneby means of a pump, the inlet port of which is connected with a pipeclosely adjacent the bottom of the tank. This pump may be placed in anyconvenient position. I have shown the same as seated within the bottomof the tank adjacent the one being cleaned. This pump 23 has an inlet orsuction line 24 directed through the wall between the two tanks andacting, to withdraw the cleaning liquid together with the sediment andthis liquid is pumped out through the line 22 to the wing tank 7, wherethe sediment will settle out therefrom and the same cleaning liquid usedover again.

In carrying out this process, the interior of the tank may be Washedfirst with hot water. The Water, after being heated in the wing tankthrough the heating coils, or through any other suitable means, ispumped under heavy pressure against the interior of the tank, removingthe-sediment and the rust and washing the same to the bottom of the tankwhere it is at once removed. The removal of the cleaning liquid allowsthe streams of cleaningliquid which are directed against the bottom: tohave a full cleaning effect thereon in the same manner as it has againstthe side and top walls.

The cleaning liquid proper is usually kerosene or some similardistillate which is heated and directed against the sides of the tankand the pumping of the same against the wall with force removes the rustand sediment from all the corners and crevices between the plates andthe framework and washes it down to the bottom where it is at onceremoved. This process may be 'continued until the interior is entirelyfree of foreign material. This may take from four to eight hours,depending upon the state of the interior of the tank before the cleaningis begun.

In carrying out my improved method, it is essential that the pressureemployed be sufiicient to erode or cut the scale and other sediment fromthe surface to be cleaned, and the initial pressure of the jets orstreams as delivered into the tanks by the nozzles should not besubstantially less than forty pounds to the square inch or 'even inthose cases where the splashing reaction of the 'e'ts is 4 or evenhigher, is employed. F urthermoref the surfaces to be cleaned andparticularly the bottom of the tank, wherein the greater f part of thesediment tends to collect, should be maintained substantially bare, thatis, a large volume of liquid should not be allowed to collect thereonduring the cleaning operation, in order that the high pressure jets maydirectly impinge against the sediment, rust, scale and like material tobe eroded and to be removed, and accordin ly, for this purpose, thesuction pump emp oyed for the removal of the liquid from the bottomofthe tank should be positioned aft as in any empty vessel the draughtwill be this aft ,end will be the low point of the vessel, and thereforthe suction pump should be so positioned that it will be in the aft. endor Whatever other osition is substantially the lowest point of t lievesselso that the sur faces to be cleaned are substantially kept clearof a butler layer of cleaning liquid which is being recirculated throughthe vessel to be cleaned.

M improved process not only enables me to e ect the cleaning of cargotanks at from 50% to 75% less cost than other processes now in use, butit accomplishes the cleaning of the ships pipe lines, pumps and valvessimultaneously with the cleaning operation,

as I preferably include as part of my system the ships pump and pipelines, and it thereby becomes unnecessary to renew the packing in thepipe system or open the'valves or customarily now the case when thecleaning of the ship is undertaken. i In order to prevent the cleaningfluid, particularly when kerosene is employed for this purpose, frombeing too rapi ly volatilized, I cause a solid jet of the same tobepropelled through the nozzles which deliver into the vessel beingcleaned instead of effecting the introduction of the liquid in the formof an atomized spray.

When the cleaning operation is finished, it is preferred to remove thesmall residual body of liquid which may collect in the low point of thevessel when the operation of the apparatus is stopped by means of avacuum pump or manually, as desired.

This method of cleaning the interior of tanks is not only quicker in itsoperation and more economical to carry out than is the old process, butitis much less harmful to the interior of the tank. All of the'sides ofthe tank areequally heated through the oil so such that thatthereis nounequal strain on the rivets.

Also all portions of the interior of the tank L are equally clean. Allof the rust and'scalc can be thus removed so that no gas formingsediment can be left upon the walls of the tank. The vbottom of the tankis cleaned the tank may be used for the lighter distillates withpractically no discoloration whatever to the liquid being carried. Italso eliminates danger and discomfort to men who. under the old method,are compelled to enter the tanks to scrape and brush the surfaces, andeliminates exposure of these men togas and the heat. The furtheradvantages thereof will be obvious to those skilled in the art.

"The ejector nozzles are, positively driven through gearing instead ofreliance being placed upon the reaction obtainable frpm the highpressure of the liquid circulating therethrough to revolve the samesince, owing to the unevenness of the surface upon which the highpressure jets im inge due to obstructions on the inside of tan ers, suchas iron cross beams, there is a counter reaction transmitted back to thenozzles from the uneven surface of the tank and, due to the fact thatthey are arranged in pairs so as to counterbalance each other, theywould if the reaction of the jets were the sole motive power cease torotate entirely under certain conditions.

One of the principal advantages of my improved system resides in thefact that no preliminary steaming whatsoever of the tanks to be cleanedis-required either for the purpose of gas-freeing the same or forrendering the heavy oil residuum susceptible to removal't't.,Asaconremove the pump heads or p p fittings as is by the highpressure lmpac e s sequence the deterioration of tankers and othersvessels due to the expansion'and contraction strains under steaming withthe consequent loosening of rivets and the acceleration of corrosionresulting from steaming operations is avoided while at the same timeowing to the terrific direct erosion and melting action and secondaryreflecting, splashing or rebounding action of the hot high pressureimpact jets, it.is possible to completely gas-free and otherwise cleanevery crevice cleaningas well as the complete gas-freeing,

without the necessity for resorting to steaming with its attendantdirect and indirect expense, are startling.

Where light :oil, such as gas oil or kerosene for example, is employedas the circulatory cleansing liquid, it will dissolve theotherwisevirtually useless bottom oil sediments or residues that can berun through the crack ing stills of a refinery, thus greatly reducingthe cost of the cleaning, since the cleaning oil will be increased inbulk proportionate to the amount of residues dissolved therein.

Furthermore the residues, which are stripped or eroded as minute orsmall particles or droplets from the tank bottom and sides and the shipspipe lines as well, will float upon or be carried oif with the drawlating liquid. As a consequence, neither the pump lines nor the pumpwill be clogged up during the pumping operation with the gobs orsnake-like strings of residuum from the tank, so that the cleaning isaccomplished continuously without any halts or shut downs being requiredto blow out the accumulated masses or gobs of residue from the hose, thepump lines or the pump itself, and in this respect my process differsmaterially from other pumping operations now resorted to for p removingbottom residues from tanks and tankers.

What I claim as new is:

1. A recess of cleaning the interiors of tanks cargo-vessels and thelike comprising heating a cleaning liquid, directing the said liquid instreams with force against the sides and the bottom walls of said tanks,and

simultaneously removing the used liquid at a rate to maintain the bottomwalls free of liquid and in condition to be cleaned by the sameoperation.

2. A recess of cleaning the interior of oil tanks 0 the characterdescribed comprising fiushing the interior thereof with a jet'ofhotwater, removing the used water and sediment, then directing a solidjet of hot kerosene with force against the bottom and other walls ofsaid tanks, and maintaining said bottom walls approximately free ofliquid and sediment to permit direct contact of said jets therewith.

3. In the process of cleaning oil tanks to remove residual deposits andgases therefrom, the step which comprises the repeated circulation ofjets of hot water through said tank under high pressure while removingthe introduced water at a rate sutficient to maintain the bottomsubstantially bare of an interposed bufier layer of cleansing water.

4. In the process of cleaning oil tanks to remove oil residuumtherefrom, the steps which comprise delivering an impact jet of cleaningfluidinto the tank to be cleaned -n an arcuate path under a high initialpressure and in excess of -75 lbs. and during bottom of said tanksubstantially bare of charged into the tank as high pressure splash--ing impact jets under a pressure of not less than 7 lbs. per square inchand portions of the liquid being withdrawn from the tank at a ratesufficient to substantially maintain the tank in a stripped conditionand thereby avoid the interposition of a substantial buffer layer ofliquid in the bottom of the tank and to thereby insure the directimpingement of the jets on the accumulations of dislodged residues,and,without substantially changing the zone of delivery of such jetsinto said tank, causing said jets to travel in predetermined butconstantly changing aths.

In testimony whereof I hereunto afiix fii signature this th day ofSeptember, A. D.

ARTHUR B. BUTTERWORTH.

the delivery of such cleaning fluid maintaining the

